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MG MGA - Help with carb spindle replacement

I've nearly completed my carb rebuild. They were in HORRID shape ... the front one had severe varnishing on the outside of the carb body and a frozen float valve, which leads me to believe it was leaking massive amounts of fuel.

The spindle rods are pretty severely worn and I have replacements. The problem is that I'm unable to remove the throttle levers from the old rods. I ruined one of them by drilling the old spindle out of it, and then read the manual and saw a pin of some sort holding it in place. How do you remove this pin?

Also, my replacement spindle rods from Moss don't have any sort of hole for the pin to go through. How do I install the throttle lever on the new spindle?

Thanks,
-Rich
R Stokes

Barney Gaylord lives in Naperville. His website:

http://www.mgaguru.com/

He has helped others in the past but, obviously, he doesn't work for me. He knows more about MGA's than most.

Bill
Bill Eastman

I can't remember how I got the pin out, seems to me it wasn't difficult. The hole for the new pins is drilled after everything is together so that it is in proper register, with the throttle closed and the arm in the correct location. Probably best to just mark the drill point on the shaft and then disassemble and drill on a drill press. Have you inspected the carb bodies for wear in the shaft bore? If they are generally as bad as you indicate, they might need to be sleeved. Also inspect the choke levers for elongated holes. If they are worn much you can never get the idle set correctly if the choke is used.
John DeWolf

Rich,

The first thing that I would do before I went any further is to fit the throttle spindles to your carbutettor's and check the fit. After this check (spindle to bushing wobble not to exceed .4mm or .010") and if you find that the bushings require replacement, I would STOP there and send them out for professional throttle spindle/bushing rebuild. Specialized equipment is required for drilling out the bushings, replacement to ensure the concentricity and line reaming.
If you find that your bushing are within acceptable tolerances, proceed as follows:

First remove the tapered pins that hold the throttle shaft arms on by using a drift (rod or punch) that is slightly less than the 1/8" drilled hole going through the throttle spindle. Examine the exposed portion of the tapered and push out from the opposite side of the exposed pin. To do this, you can use your vise and open it up just enough to cradle the throttle shaft arm or make yourself a suitable cradle out of scrap wood. Drift the pin out. Find yourself a replacement shaft arm for the one you damaged. I don't know if Moss has them. If not, contact me off line and I will direct you for a replacement.

Secondly, note the throttle shafts are of unequal lengths. Insert the proper end in the carburettor body along with the butterfly, Make sure you put the butterfly in the right way. Insert the screws but do not tighten them! Assemble the brass retainer, spring and tensioner that holds the spring to the shaft. Rotate the tensioner 180 degrees and tighten the 1/4" hex nut. With the butterfly now closed off in the throttle bore-slide the throttle arms onto the spindles to their respective positions. Slide them on until they are .025" from the cast boss of the carburettor body. Put a shim or whatever you have to maintain this distance. Now set up the throttle shaft position: Cut a piece of coat hanger wire and place it between the outer diameter of the butterfly and carburettor body until the butterfly is suffciently cocked at an angle so that the hole in the throttle stop is parallel the mounting face of the carburettor body. If this is confusing, practice assemble up one of the old spindles and insert the coat hanger wire until the hole is parallel.
Now comes the tricky part of drilling the hole through the spindle so that it lines up with the hole in the throttle shaft arms. To do this, you need a dril press or a friend that has one. Don't do this with a hand drill! Secondly, make yourself a fixture to hold the carburettor while drilling. You can do this simply by making a right angle fixture made of wood where one face mounts the carburettor body and the other face mounts or is clamped to the drill press. Just make sure that the faces of your fixture are perpendicular to each other. Once your all set up with the throttle arm properly positioned. Remember the spacing from the body and that when the wire is removed the butterfly is closed and the throttle stop position allows adjustment. Drill a 1/8" hole through the spindle and insert the tapered pins in the opposite side that they came out. Good luck! It is not that hard. Just think and act the whole thing through before proceeding. Proper fitting of the butterflies, upper/lower jet bearing assembly to preclude leakage, dashpots and fuel bowls is another topic. Best regards, Don Tremblay
Don Tremblay

Rich,

I was re-reading the above missive and noted that I should have said that the throttle shafts are of unequal lengths relative to the position of the machined slot for the butterfly. Don
Don Tremblay

Rich...ever hear of a can of worms...LOL!

If you want to have a go Rich, Bill and John have good advice. Don has laid out the big picture just fine, though there is always more than one way to skin a cat.
You test the shaft fit easiest with a new shaft in position...not too exceed 0.005" wobble up AND 0.005" down for a total of 0.010" movement. But how, eh? One could set-up a dial indicator, if it's available and one knows how to set-up. They don't actually wear the carb bushes just up and down though. If you possess machinist experience...all this is quite simple.

If you pass the fit-approval stage, the taper-pin's smaller end probably shows a bit of a nub in the center (the fat side is normally flatter and even at the surface level. You are driving it out by punching the nubbed side inward and thru...and I do suggest supporting the lever on wood (line-up cross grain so you don't split it) with a ~3/16" hole for the pin to go into...
Definitely use a drill press when drilling for the pin install.
Just be sure that when the disc is mounted and the upper edge of the disc seats against the upper inside of the body...that the stops need the space for adjustment. If you drill and pin the lever to the shaft, insert the shaft and mount the disc and the lever stops before the disc seats on the body...you will never idle down with that shaft installed. It can be flipped 180 and used on the other side if redrilled. All shafts I got from Moss were Long in both directions, so it can probably be fitted at 180 on the same carb. Note which sides are longer (if at all) on your original shafts in case you can't flip 180 for redrilling.
Again...my technique differs somewhat. If need be, you can email me, but Don's method is super. Here's wishing you success 1st time. Cheers
Jon Bachelor

Rich,
If you decide to farm this job out there is a fellow, Tom Bryant, in Maine (207 443-6338) who will re-bush your carbs and install new shafts, or do a complete rebuild. He uses Delrin for the bushings. I'm currently having this done. My friend had it done about 8 years ago and his carbs have been excellent ever since.

Regards,
GTF
G T Foster

Gentlemen,

Thanks for your help. With the help of a 7/64" drill bit, a drill press, and a vice, I was able to remove the old throttle arm and mount it on the new arm. The old spindle was very worn, and the new spindle is nice and firm in the bearings.

One potential problem with this operation is that there are now tiny brass filings on the outside of the carburetor. My guess is that it would not be good for these to make their way into the engine. What's the best way to remove them?
Rich

Rich,
Spray down the carb with carb or brake cleaner. The pressure in the cans is usually enough to force small particles away from wherever they are. I usually use it to remove particles in small areas where I cannot reach with a brush or other such item. The use of a liquid rather than air also helps to keep the particles from going where you don't want them to go.
mike parker

This thread was discussed between 06/07/2005 and 10/07/2005

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